From wood to bone: New processes to develop hierarchically organized bone scaffolds with biomechanical performances

The development of innovative ceramic scaffolds for bone substitution with superior biomechanical features and smart anisotropic performances was performed through chemical and physical transformations of natural hierarchic structures, as trees, shrubs, palms, etc. The aim is to develop final structures highly organized from the molecular to nano, micro and macro-scales, with extremely functional architectures and ,similarly to natural structures, able to constantly adapt to ever changing mechanical and bio-functional needs. According to the bone specific characteristics, specimens derived from plants were selected, then pyrolysis process was set up to produce carbon templates. Infiltration processes were studied to transform carbon templates into CaC ₂ and finally Ca-based phosphates were prepared by multi-step thermal and hydrothermal treatment in controlled environment. To mimic the whole structure of bone with its cortical and spongy morphologies, graded 3D-devices were designed using the developed hierarchical organized material as external cortical shell and biologically inspired hydroxyapatite-collagen nanocomposite as internal bioactive spongy core.